Hardware Interrupt - Fujitsu MB90460 Series Hardware Manual

CHAPTER 7 INTERRUPT
7.4

Hardware Interrupt

The hardware interrupt function temporarily interrupts the program being executed by
the CPU and transfers control to a user-defined interrupt processing program in
response to an interrupt signal from a peripheral function.
The extended intelligent I/O service (EI
type of hardware interrupt.
■ Hardware Interrupt
●
Hardware interrupt function
The hardware interrupt function compares the interrupt level of the interrupt request signal output by a
peripheral function with the interrupt level mask register (ILM) in the CPU processor status (PS). The
function then references the contents of the I flag in the processor status (PS) through the hardware and
decides if the interrupt can be accepted.
When the hardware interrupt is accepted, the CPU internal registers are automatically saved on the system
stack. The currently requested interrupt level is stored in the interrupt level mask register (ILM), and the
function branches to the corresponding interrupt vector.
●
Multiple interrupts
Multiple hardware interrupts can be activated.
●
Extended intelligent I/O service (EI
2
EI OS is an automatic transfer function between memory and I/O. When the specified transfer count has
been completed, a hardware interrupt is activated. Multiple EI
2
EI OS processing, all other interrupt requests and EI
●
External interrupt
An external interrupt (including wake-up interrupt) is accepted from a peripheral function (interrupt request
detection circuit) as a hardware interrupt.
●
Interrupt vector
Interrupt vector tables referenced during interrupt processing are allocated to memory at FFFC00
FFFFFF
See "7.2 Interrupt Causes and Interrupt Vectors", for more information about the allocation of interrupt
numbers and interrupt vectors.
126
2
OS)
. These tables are shared by software interrupts.
H
2
OS) and external interrupt are executed as a
2
OS requests are held.
2
OS activation does not occur. During
to
H